complex presented higher reactivity in the transferhydrogenation (TH) of ketones in 2-propanol. Experimentally, it was established that both the benzimidazole and amine N–H proton played a vital role in the enhancement of the catalytic activity. Utilizing this system a wide range of aldehydes and ketones were reduced efficiently. Notably, the TH of several imines, as well as chemoselective reduction of
Reductive amination of various ketones and aldehydes by transferhydrogenation under aqueous conditions has been developed, by using cyclometallated iridium complexes as catalysts and formate as hydrogen source. The pH value of the solution is shown to be critical for a high catalytic chemoselectivity and activity, with the best pH value being 4.8. In comparison with that in organic solvents, the reductive
An iridiumcatalyst enables the reductive amination of carbonylgroups with unprecedented substrate scope, selectivity, and activity using formic acid as the hydrogen source (see scheme). The catalyst system provides significant improvement over commonly used boron hydrides.
Palladium-Catalyzed Aerobic Oxidative Cyclization of <i>N</i>-Aryl Imines: Indole Synthesis from Anilines and Ketones
作者:Ye Wei、Indubhusan Deb、Naohiko Yoshikai
DOI:10.1021/ja3030824
日期:2012.6.6
We report here an operationally simple, palladium-catalyzed cyclization reaction of N-aryl imines, affording indoles via the oxidative linkage of two C-H bonds under mild conditions using molecular oxygen as the sole oxidant. The process allows quick and atom-economical assembly of indole rings from inexpensive and readily available anilines and ketones and tolerates a broad range of functional groups
The chiral phosphoric acid catalyzed enantioselective transferhydrogenation of various ketimines was achieved by the use of 2-aryl indoline as the hydrogen donor. Corresponding chiral amines were obtained in good chemical yields with excellent enantioselectivities.